AI-S won't work in "S" or "P" modes

Discussion in 'Nikon' started by jay_drew, Jun 6, 2013.

  1. Hello all
    I've been trying to figure something out for some time. Due to the fact that none of my AI-S lenses will stop down in Shutter of Program perfected modes, I just assumed that I was misunderstanding the below statement. I have a F4; F4s; & F5, & I can only get them to stop down in Manual & Aperture preferred. Well I've reread it straight from Nikon & I don't see how I could be misunderstanding it.
    "Glossary of Nikkor lens terms:"
    "AI-S: Automatic Indexing (modified)
    AI-S coupling is a refinement of AI and became standard in 1982. The diaphragm action in an AI-S lens is compatible with Nikon cameras that allow the aperture to be controlled from the camera, as is required for programmed and shutter-priority automatic exposure control. All AF-Nikkor lenses, as well as most manual-focus Nikkor lenses made since 1982, are AI-S."
    More specifically:
    "The diaphragm action in an AI-S lens is compatible with Nikon cameras that allow the aperture to be controlled from the camera, as is required for programmed and shutter-priority automatic exposure control."
    There it is from the horse's mouth. Do the F4; F4s; F5; control the lens stopping down in S & P modes? I would think so.
    Am I misunderstanding the above paragraph?
    Are F4s; F5s incapable of stopping them down in S or P modes?
    Am I not connecting the AI-S lenses properly, or engaging the proper setting?
    Worst possibility yet, I've damaged something in the camera or lens mountings?
    Could there be another area of control of the cameras that I've missed?
    Can someone please explain why my F4; F4s; F5; will stop down all my AF lenses in any mode, but will not stop down any of my AI-S lenses in shutter preferred or program mode?
    I would really appreciate some enlightenment about this question, Jay Drew
     
  2. You have three different cameras and presumably more than one AI-S lens, and no combination of them works in shutter priority or program modes? That's bizarre.
    I have never had any trouble in any AE mode with AI-S lenses on my FG, which is the only Nikon I own that has program mode.
     
  3. Did you set the aperture ring on the lens to the smallest (orange) aperture?
     
  4. Dear Jay. You misunderstand the whole thing. All the cameras, even the first Nikon F has the feature to automatically set the aperture, at the moment, when you releasing the shutter, to the "PRESET" aperture. All nikon lenses, except 28 & 35mm PC, 2.1 cm f/4, has automatic aperture indexing. All the AI or AI-S lenses are full open, all the time, regardless what you aperture presets, like f/2.8, 3.5, 5.6, or 22, and when you releasing the shutter, it closes down to the preset aperture number. And it is the same of the more modern cameras, like the F5, F6 and the digital all electronic cameras. The modern chipped AF lenses are different. Those lenses has to have the aperture set to the smallest aperture, which depend on the lens smallest aperture.
    One more time; Those AI lenses work on the modern cameras only in M manual or A aperture priority mode, but you has to set the aperture to the required numbers, what ever aperture you desired to use. AI or AI-S lenses workin only, in Manual or Aperture prority mode. F3 to F6 and all DSLRs.
    ""The diaphragm action in an AI-S lens is compatible with Nikon cameras that allow the aperture to be controlled from the camera" no, it is not.
    I hope, you going to understand my pure English grammar.
    Cheers.
     
  5. Jay -
    On the Nikon F4s ...
    Pre-Ai lenses have to be stop down metered and work only in A and M modes.
    Ai'd, Ai and Ais lenses work fine only in A and M modes.
    AF, AF-D, AF-S and AF-I lenses work fine in P, S, A and M modes.
    VR lenses don't have VR capability.
    G lenses are ok only in P and S modes.
    That's the way it is so far as I know.
    See and save the following for reference :
    http://www.nikonians.org/reviews?alias=nikon-slr-camera-and-lens-compatibility
    Jim
     
  6. Having looked into this a little more, it seems that Nikon's professional AF cameras (F4, F5, F6) only support manual focus lenses in manual and aperture-priority modes. To get shutter-priority or program mode to work with an AI or AI-S lens, you need the cheaper FA or FG manual-focus cameras or the N2020 (F-501) AF camera.
     
  7. AFAIK if you want to use an AIS lens in all four exposure modes, you need an FA.
     
  8. Oh, right, the FG doesn't have shutter-priority mode, just program, aperture-priority, and manual. Been a while since I've shot that one.
     
  9. Jay, revisit the poorly written but key sentence and understand precisely what's being stated: 'The diaphragm action in an AI-S lens is compatible with Nikon cameras that allow the aperture to be controlled from the camera, as is required for programmed and shutter-priority automatic exposure control.'
    1. The diaphragm action is compatible with so-and-so cameras (period!), nothing more, nothing less. It does not say which exposure mode(s) are compatible.
    2. The bit that reads: '...as is required for programmed and shutter-priority automatic exposure control' is a) parenthetical and b) only serves to confuse. (So why include it, Nikon?)
    Nikon is known for ambiguous (OK, I'll say it: poor!) technical writing.
    If you set the Exp Mode to P or S on the F4 or F5 when using a manual focus/non-CPU lens, the cameras will automatically default to A mode. The exception is an AI-P lens (manual focus with OE CPU).
     
  10. To clarify... I believe (someone please correct me if this is misinformation) that the only cameras that can distinguish an AI lens from an AI-S lens by the indent on the back are the FA and the F4. Everything else can only detect electronically, meaning that they know AF and AI-P lenses are AI-S, but otherwise have to assume a nonlinear aperture. Since everything recent relies on open-loop metering, the camera doesn't know where to move the aperture lever to. Hence you have to set the aperture manually, on the lens ring (I don't believe you can set the aperture using the camera controls manually, for the same reason).

    Yes, speaking as someone with some AI-S lenses, this is annoying. There ought to be no reason that I can't tell my D800 (say) to use my AI-S lenses with automatic aperture, but - short of chipping them - I can't.
     
  11. Andrew, the N2000 (F301) and the N2020 (F501) can also detect the indention on AI-S lenses (officially known as the Lens Type Signal Notch).
     
  12. Maybe I'm approaching it silly simple.... but with Ai/AiS lenses, I need to set the aperture using the aperture ring, while with other lenses I'd use the second control wheel for that. Given that the camera cannot move the aperture ring (only follow it), any mode where the camera can change the aperture automatically hence will not work....
    Now, maybe I am completely off the mark (with no experience at all with the F4 either).... but this way, to me it has always made sense that only A and M work :)
    Not really an answer to the question, is it?
     
  13. Thanks, Cory. I can always trust this forum for education!

    After a bit more of a rummage to try to give a better answer... it appears that the (sweet) FA supports shutter priority with AI-S lenses but it also supports shutter priority with AI lenses, because it can select between closed and open loop metering (meter while stopping down, or just move the lever to the calculated place based on the open metering). The F4 has an AI-S detect pin, but doesn't support aperture or program mode with AI or AI-S lenses (only chipped lenses), so I'm not quite clear what it does with it. The FG, F301 and F501 will do program mode (with closed loop metering) for AI lenses, and the 301/501 go open-loop with AI-s, but they don't support shutter priority.

    It strikes me that some modern cameras may not be able to do closed loop metering because the aperture lever movement is tied to the shutter release - which is why you can't hold down the DoF preview button and spin the aperture dial to see different effects on, say, a D700. You can do this on the D800 (added to allow aperture to vary during video), and on the D3 series (I presume D4 as well), so I'd expect these cameras to be technically capable of closed-loop metering had they been programmed to do so. Since an AI-S lens ought to open-loop meter in just the same way that an AF lens does, that shouldn't even require any technical changes to the camera; I presume Nikon simply felt that people should buy AF lenses if they care.

    For those four cameras - especially if it didn't have any significant effect on the F4 operation - I kind of feel that there's a little grinding wheel somewhere in the Nikon factory that's been taking chunks out of the back of lenses for thirty years. It probably doesn't feel very good about itself anymore, but I guess it's a living.
     
  14. Crossed over with Wouter...

    There's no difference in the aperture ring behaviour between an AI-S lens and an AF lens; the only difference for an AI lens is that the aperture lever movement may not be linear with the change in aperture. The aperture ring does two things: tell the camera what aperture you've selected (via the feeler around the lens mount) and block how far the aperture lever can move - which is why changing the aperture ring position changes what you can see when you look through a lens that's not on the camera.

    When you set the aperture ring to its minimum position, you're allowing the aperture lever to move over its full range. At that point, a camera can choose where to move the lever to, which is why the camera can control aperture electronically.

    The only difficulty for a manual lens should be distinguishing between AI and AI-S, thereby telling the camera whether the aperture lever controls the aperture in the same predictable way as with AF lenses (the lens is AI-S) or whether the effect of the lever on the aperture is nonlinear (the lens is AI - in which case you either have to meter while you're closing the lever so you know when to stop, or just give up). The cameras with the pin to tell AI and AI-S apart know which they've got; nothing recent has the pin, and therefore assumes AI.

    Given that, for DSLR use, we already tell the camera the aperture and focal length of an AI lens so it can meter properly, not being able to tell the camera that the lens is AI-S while we're at it seems a bit remiss. I can understand not adding an open loop metering mode, but not being able to tell the camera that it can use closed-loop metering is annoying.
     
  15. Andrew.... I am sure my post was technically without any foundations whatsoever, it's just how I "sell" this limitation to myself as logical.... no more than that. Otherwise, I am taking in what I read to the extend I did not know yet... and yes, it seems a bit a waste to let AiS functionality go. But, as I always already was a A and M shooter, to me it's never actually had impact on what I do anyway... which explains my lack of knowledge on the point :)
    Just wondering, on the cameras that have this pin to distinguish between Ai and Ais, how vulnerable is it? Sounds like the most logical explanation for Nikon to not include it anymore?
     
  16. Honestly, I spend most of my time in aperture priority and manual as well - but it helps that the recent cameras have auto-ISO. (I used shutter and program modes more on my Eos 300D, which only did partial auto-ISO in scene modes.) Now, if someone were to make a film camera that could dynamically swap different speeds of film in according to the meter reading... it would be a bit tricky to handle. Though you could stick a variable ND filter in there at a push.

    (Completely off-topic, could someone point me to an explanation of how the switchable ND filters in digital compacts work? I can't think of a way of doing it without physically moving a filter or blocking a minimum of half the light with a polarizer or overlapped filter layer, and I presume neither of those are how it's done. This has been bugging me.)

    II assumed leaving off the AI pin was just a cost-saver; it can't be much more vulnerable than the lens release pin, and once there was an electronic interface anyway, a separate switch is fiddly to add (especially in a strange place on the mount). I guess a switch might be more failure-prone than a solid-state connector. Still, I'm not asking for the switch back, just the ability to tell the camera what it would have been saying! Maybe Nikon felt that customers couldn't tell AI from AI-S - or that F4 owners (who might have wanted to have shutter priority) would upgrade to AF anyway.
     
  17. All the confusion was because Nikon tried to preserve the Nikon F mount which is a good things but created a lot of incompatibility issues. Canon avoided the whole thing by switching to a newer mount which pissed off a lot of its customers but in the end it did save a lot of troubles.
     
  18. Apparently, in both the cameras with CPU communication with the lens and with the cameras without it, (FG, FA, F301, F501) automatic aperture (in P & S mode) is set by the camera using the same method, moving the lever on the body... However, Nikon has disengaged the ability to do so on the cameras that bare CPU contacts & control the lens from the body, because the control of the aperture in M and A modes (in AI lenses) is done using the wheel on the camera! This means, that the metering is calculated by internal circuit and the spring controlled ring around the mount is inactive on those cameras. In the cameras without CPU contacts, all metering is done by the ring around the mount, on the rest, the ring is there (if it is) to activate a parrallel path to the internal metering of the camera which is connected with the control wheels of aperture and shutter speed, if Nikon was to activate the ring around the mount for automatic aperture, then the aperture wouldn't be able to be controlled using the camera dials in A & M modes! ...now which modes are more important? ...well done Nikon, it's great to be able 40 years old (lovely) lenses with metering in a modern AF DSLR!
     
  19. Theo - I'm confused. The aperture lever on any Nikon body still controls the aperture setting on every Nikon lens other than the TS-E lenses and the new 800mm f/5.6 (which have Canon-style electronic apertures), and those lenses which have no aperture lever at all. The ring is just a ring - it doesn't "do metering". The problem with using the lens ring for automatic aperture is that it provides a hard block for the smallest aperture which can be selected - which is why you have to move the ring (which isn't strictly speaking "deactivated") to its minimum aperture size setting before giving the camera control over the aperture.

    On a camera like the D700 (say) you can tell the camera you'd like to use the aperture ring on the lens. Indeed, you have to for AI lenses (and less justifiably for AI-S). While some would find it useful, I don't think it's possible to have easy-ISO, aperture ring aperture setting and shutter speed set by dial - i.e. three-dial full-manual mode - at the same time; please someone correct me if I'm wrong.

    Anyway... you're right that the lens aperture dial has to be set to minimum aperture in order for the camera to control the aperture setting, whether it does so through automatic exposure or through the user explicitly setting an aperture via the command dial. However, this is somewhat separate from whether the camera has a dial for doing so - the F4 doesn't have an integrated aperture dial, for example, and therefore can't use G lenses in aperture priority, even though it understands electronic connections. I'm a little unclear whether that was the point you were trying to make, or whether I've misunderstood. Could you please elaborate?

    There are reasons I'm happy with the camera being used to control aperture - it makes much more sense with variable aperture zooms, and for big telephotos (that are well suited to SLRs) my hand is usually a long distance from the aperture ring (and AF mode switch, not that I'm still bitter about that...). There are reasons it's nice to have a third control dial around the lens too, particularly for a smaller design - which is why Fuji's rangefinder-style cameras do that, as (for mechanical reasons) do Leicas. I can understand the shift to G lenses, but I'm sympathetic to those pointing out, for example, that aperture variability messes with time lapse photography. In any case, since the restriction on AI-S shutter priority seems to be arbitrary, it's a little annoying. I'd be more annoyed if I'd just bought an F4, when the camera first came out and there weren't many AF lenses.
     
  20. Some aspects of the aperture handling system are annoying - for example, my F100 lets me change a setting and then use the aperture ring on an AF lens that has a ring, but my D800 doesn't. If the D800 allowed the use of the ring, it could free up the wheels for other uses - e.g., you could have aperture, shutter and ISO control quickly while looking through the finder. Since the camera knows full well what the lens is and can read the aperture from the AI feeler, and the setting would let it know that I didn't turn the ring by accident, I can't see any good reason not to have that work.
    But overall the annoyances with the number of features implemented or not implemented in aperture controls is surely outweighed by the benefits of preserving most of the compatibility with older lenses. Aperture rings wouldn't be there at all if Nikon had pulled a Canon/Minolta and changed the lens mount. Since all compatibility with manual lenses and ability to use aperture rings is a bonus, when compared to the compatibility we'd have if Nikon had changed the mount, any actual detriments arising are of the consumer confusion type and could be resolved by reference to the literature.
     
  21. Some aspects of the aperture handling system are annoying - for example, my F100 lets me change a setting and then use the aperture ring on an AF lens that has a ring, but my D800 doesn't.​
    I can't say I've every actually done this for a lens that's not AI, but menu option f9 lets you decide whether the aperture will be set by the lens ring on a D800. Like I said, I don't believe you can tell the camera to reuse the dial that would have been aperture for easy ISO, though (leaving the other ring as shutter speed, in manual mode). If it works, and I've not actually tried, I might start using that mode. My habits are ingrained from my D700 ownership, and it didn't have easy-ISO, so I may be missing a trick. (And I do appreciate the ability to use an AI-S lens on my D800. Though I could also use it on my Canon DSLR via an adaptor!)
     
  22. Whoa, you're right - I can use my aperture ring! For some reason I'd been convinced this was not true - I must have got the wrong information somewhere.
    (A good example of user confusion that could have been resolved by reference to the literature if I ever saw one.)
     
  23. So the new E lens isn't compatible to any cameras before the D3? Another level of incompatibility. Eventually they would come to an all electronic interface between camera and lens like that of Canon but changing a little bit at a time would seriously cause confusion.
     
  24. Yes Andrew, I thought it was a bit confusing the way I've put it... You have to excuse my English for this, not being my mother language.
    What I am saying is that they disengaged the ability (they could have it working) because if it was engaged, A & M modes wouldn't work with AI lenses, you wouldn't be able to use the alternative internal path (the in camera metering) since the aperture would be controlled by the other path (the ring) and the shutter speed by the internal path, what now happens is that is only the internal path that works (for the camera to set the shutter command, manually or automatically) and the ring is used only to provide information for the value on the aperture in use (again to the internal path). If they where to use the ring as aperture control, the metering would have to disengage the dials that are connected to it (the same internal metering) and thus the shutter dial would have to be disengaged too. I guess they could make it work, but it would be a much more expensive and complex design which possibly would become even more expensive because they would have then to design 2 different control systems (one for the cheaper models that don't have the ring at all). Now, they can have one control system for all cameras and only use the ring for the bodies that are to accept the AI-s lenses.
    Of course you are right on what you say about the aperture control ring on the F100 and the rest of cameras in the other comment of yours, it is there only for lenses that have an aperture ring, but CPU as well... the mount ring isn't related with lenses that have CPUs... what is replaced, is the aperture control of the camera with the aperture ring on the lens.
     
  25. BeBu: The TS-E lenses have a manual aperture setting button that you can use to close the aperture if you're not on a camera that knows about "E" lenses (just as my Hartblei and Kiev T-S lenses let you toggle manually between wide open and the selected aperture). Metering tends to be iffy with tilt-shift lenses anyway. I've not investigated the 800mm, but I suspect it's genuinely limited - expecting the user to stop down manually when using an 800mm lens is unlikely to be appealing. If someone would like to give me one of those lenses, I promise to report back. :) (But I do think Nikon should have gone all-electronic some time ago, even if they'd provided a backward-compatibility path. On the plus side, adapting EF lenses to other platforms is annoying because there's no mechanical way to move the aperture.)

    Theodoros - no need to apologise, I'm the confused one!

    The aperture ring does need to be set to something in order to allow the camera to control the aperture (for S and P). Some camera designs have an explicit "auto" setting on the aperture dial - my Pentax 645 does, for example - but Nikon were stuck because the lens mount predated the need for this. So long as there's another way to tell the camera to take control of the aperture, all the aperture ring actually has to do is get out of the way (which, since it mechanically restricts the movement of the aperture lever from wide open to the value that's set, means that it has to be set to the smallest aperture if the camera is to take control of the full range). The cameras with automatic aperture with AI lenses control how far the aperture lever has moved (for auto aperture), or release it completely and let the aperture ring control limit its movement (for manual aperture). The same happens if you tell a D800 to use the aperture selected on the lens ring rather than internally - the difference is that you have the option to tell the newer cameras what aperture you want explicitly via a dial, as well as by the lens ring. With an AI-S lens, the camera should know exactly how far to move the lever to achieve the aperture you request, as it does for AF lenses; for an AI lens, the camera doesn't know.

    I may be over-stating the point; I just want to be clear (or corrected!) that the mechanism of metering and aperture control is identical for AI and AF lenses, and that it's just the AI/AI-S distinction of whether the camera knows the lever position for the selected aperture that's distinct - hence my claim that AI-S lenses should "just work" if the camera knew it had one attached. Unless anyone knows a good reason otherwise!

    To clarify, there's no "disengaging": all the cameras that can do this at all have purely electronic controls. The aperture following ring around the lens mount, which engages with the aperture ring, just feeds a number into the camera meter electronics to tell it what aperture you selected. An equivalent number may come from the system of spinning a dial (and the number is just stored in software in that case - which is why there's no hard stop on the control dials when you use them for aperture, and why you can change the stop size change for each click in a menu) or from the camera's selection in auto-aperture mode. All this tells the camera what settings to use for the exposure and whether the exposure is "correct". I don't actually know whether the camera will try to move the aperture lever to where it thinks it should go even if the aperture ring is being used to set the aperture, or whether in this case the camera will fully release the aperture lever and let the aperture ring catch it - does anyone know? Either way, the meter is unaffected - the camera thinks the aperture will be set to the value it expected when the shutter was pressed. Low end DSLRs with no aperture ring following tab (though they do have a switch to detect whether minimum aperture has been selected, I believe) still control the aperture lever in the same way.

    The cameras that can do auto-exposure with AI lenses are different: For an AI lens, the aperture is stopped down progressively until the meter detects the appropriate aperture, then the mirror is flipped up and the exposure taken. For an AI-S lens, the cameras which know about the linear aperture will meter only while the aperture is open, move the aperture lever to the desired location while the mirror flips up, then do the exposure without checking the meter reading (this being faster), just as recent cameras do with AF lenses. There's an animation of the aperture lever (on the left) moving while the mirror is flipping up, in this case from a D3, here. The distinction between the two cases will be electronic, though - it's only one mechanism.

    I'm not sure whether we were actually disagreeing about how this worked, but if we were, I hope that's clarified things!
     
  26. " I just want to be clear (or corrected!) that the mechanism of metering and aperture control is identical for AI and AF lenses, and that it's just the AI/AI-S distinction of whether the camera knows the lever position for the selected aperture that's distinct - hence my claim that AI-S lenses should "just work" if the camera knew it had one attached."
    Actually Andrew, the camera "knows" when it has an AI/AI-s lens attached by detecting the movement of the ring around the aperture mount which also provides the aperture setting as info to the metering... Notice that when an AI or AI-s is attached, the ring is "grabbed" from the lens and is moved, the same doesn't happen with a G lens. What opposes the automatic aperture lever on the back of the lens to set the aperture automatically, is that the lever cannot be controlled by the coupling ring around the mount, it must be controlled by the camera dials because the dials are connected with the metering, Thus, if the system (the way it is designed) would give the ability to the ring around the mount to be an extra control to the metering, both the other controls on the camera (the aperture and shutter dials) would have to be disengaged, then the camera would be able to do S & P modes, ...but not M&A (!!!). Obviously they could design a more complex system and have everything working, but this would cost much more, because other that it is more complex, they would need to have a different (much cheaper) system to control the cheap cameras that have no AI coupling... while now, they have one (cheap) system for all cameras and only add the coupling ring to the more expensive models.

    "To clarify, there's no "disengaging": all the cameras that can do this at all have purely electronic controls. The aperture following ring around the lens mount, which engages with the aperture ring, just feeds a number into the camera meter electronics to tell it what aperture you selected. An equivalent number may come from the system of spinning a dial (and the number is just stored in software in that case - which is why there's no hard stop on the control dials when you use them for aperture, and why you can change the stop size change for each click in a menu) or from the camera's selection in auto-aperture mode. All this tells the camera what settings to use for the exposure and whether the exposure is "correct". I don't actually know whether the camera will try to move the aperture lever to where it thinks it should go even if the aperture ring is being used to set the aperture, or whether in this case the camera will fully release the aperture lever and let the aperture ring catch it - does anyone know? Either way, the meter is unaffected - the camera thinks the aperture will be set to the value it expected when the shutter was pressed. Low end DSLRs with no aperture ring following tab (though they do have a switch to detect whether minimum aperture has been selected, I believe) still control the aperture lever in the same way."
    Exactly! Only that the AI coupling ring is not engaged as a dial (it only provides info to the metering)... if it would (be engaged) the camera dials would have to be disengaged (which would lead in S&P working and A&M not working) ...look above.


    "I'm not sure whether we were actually disagreeing about how this worked, but if we were, I hope that's clarified things!"
    We fully agree on how it works, my comment is only on why there is no full compatibility on all modes... Just another point if I may... The metering is in full communication with both the camera dials, if the coupling ring was to act as a dial, the matrix metering mode would also work (as it does with the FA), the reason that matrix now doesn't work with AI/AI-s lenses, is that the coupling ring only gives aperture information, it cannot act as a dial!
    I have to say that I love the system the way it is! I never use S or P modes and have plenty of AI-s lenses in my possession. In another conversation I'll present a "trick" on how I have convert (harmless and easily reversible) my 14mm f2.8 to an AI-s lens. I would do so with the 17-35 too, but AF zooms don't have a "real" DOF scale on them, pity! I may still do it though, I love using the aperture ring manually the traditional way.
     
  27. Aahh... Andrew, another proof that the camera knows that there is an AI/AI-s lens attached, is that it automatically turns non-CPU lens data to ON! Only that the system is a bit "stupid" ...and the aperture on the top screen is the one detected from the coupling as if the lens was the last AI-s used... if the lens is different you have to "tell" it! ...unless of course if max aperture is the same... (In this later case all the exif data will only show wrong focal length). LOL...
     
  28. That one, at least, I can clear up. The camera isn't detecting the presence of an AI lens, it's detecting the lack of an AF lens. If you have the non-cpu lens data on a D800 set to 50/1.4, remove the lens, and turn it on, it gets no electronic signal, assumes the 50/1.4 lens is there with the aperture ring wide open (because the AI feeler is all the way to the right) and displays f/1.4. If you move the AI feeler with your finger the displayed aperture changes.
    The AI feeler is all the way to the right no matter what lens is mounted and 1 stop corresponds to the same amount of rotation on all lenses. All it's doing is, it has the wide open aperture because you input it, it knows how many stops the lens is stopped down, and it does that math. Since the understands how much light will enter the stopped down lens as a function of the amount coming in wide open and the number of stops the lens is stopped down, it doesn't actually care what you've entered in the AI lens data in the menus, it will get the exposure right anyway. The information in the menu is only there so the aperture readout and exif data will give the correct information.
     
  29. Wow! 3 pages of answers. I don't believe I've ever asked a question that generated so much activity!
    Thanks to all, I really appreciate all the answers.
    Actually the answer to my question is that Nikon's definition (& many others as a result of trickle down) of Ai-S incorrect. At my age, I'm not as sharp as I once was. I was afraid that I was making some error when trying shutter-priority. I've mes-exposed quite a few shots due to this misunderstanding. I mean the reality was butting up against Nikons word on this matter. The answer also is that I should get all auto focus lenses, if I want to work in shutter priority.
    I can always shoot manually, (I have incident, reflected, & spot meters & know how to use them) or aperture-preferred. But I prefer to let the camera set the exposure in situations where I trust it to be accurate for expediencies sake.
    The same way w/ flash, I hate to use guide #s, much too slow (I know, event & press photographers get so that they can manually set flash exposure instantaneously, but I can't).
    I prefer shutter-priority so the shutter speed doesn't creep too slow for sharp photos, I can control shutter speed w/ the f-stop, but it's not my preference.
    I'm really glad I sat down w/ most of my cameras & lenses & made a matrix of which lens will do what w/ which camera & after I knew for sure what was what, that I asked this question. I should have done this a long time ago. What I did was to take each lens in increasing focal length, attach it to each camera in a brightly lit area to see if the aperture blades ever left the smallest setting (largest #) & I would also set it to almost the max f-stop to see if it would move from there. I did this for 3 cameras; 6 lenses; & 4 modes, all the while continuing to rewind the old 'play' roll of film I had & marked the results on a matrix I had drawn up.
    This was to a limited extent the question I had asked some time back about what modes work w/ what equipment, but I expanded it to include more cameras & Nikon Flashes & cords. This (the question I just asked) narrowed it down to chewable bite. Rodeo Joe said, back then, that it looks like I have a bit of research ahead of me, & he was right. The 1st part is to figure out what question(s) to ask.
    Thanks to all, again, Jay Drew
     
  30. I think, based on how they have functioned on my Nikon/s Bela describes the way the AI/S lenses work correctly. Aperture Priority and manual only. Lens is wide open till shutter pulled and it stops the lens down then. If you want to preview the DOF you need to use the preview lever depending on which body you are using. Jay, in aperture priority mode, the camera does set the exposure, by adjusting the shutter speed to adjust to the meter reading through the lens. In cameras from FA and FE forward (I think). Its just that on AI/S lenses the camera can not set the aperture. The index mechanism only closes the aperture to its pre set (set by user via the aperture ring). Depending on the camera, the exposure mode doesn't have anything to do with program mode. In other words, on my, for instance D200 or D700, I can use an AIS in matrix meter, spot meter or center weighted in camera after setting parameters in the "non-cpu lens" setting. But I can't use any P mode where the camera chooses aperture and shutter. Only manual or Aperture priority. Clear as mud? As I recall, some Nikon models required pre-AI lenses to be shot stopped down.
     
  31. Mind you that P will also work correctly.... but in reality, it's exactly the same as using A mode because aperture can't be adjusted from the camera... Still, exposure will be correct.
     
  32. Gosh that was all very interesting.
    In fact the ring on the AI/AIS lenses doesn't feed the aperture to the camera; it feeds in the amount below maximum aperture the lens is (or rather will be) stopped down. If you put almost any lens on the camera at full aperture the teller on the camera will assume the same position confirming this fact. I said almost since the very fast lenses (f/1.4 and faster) don't seem to quite follow this rule - I read some guesses some while ago about why this was so but don't remember the details. For centre weighted and spot metering the camera doesn't need to know the actual aperture since it is a TTL meter. For matrix metering the camera does need to know since it needs to know the absolute scene brightness and the lens maximum aperture is fed to the camera mechanically on AI/AIS lenses and via the contacts on AF lenses. I believe that AFD lenses do this mechanically too so presumably they'll matrix meter on a Nikon FA.
    My understanding is that an AI/AIS lens on a modern autofocus body is stopped down by the stop down lever moving all the way like it always did; in fact I recall reading that setting a body to work this way with an AFD type lens if a good idea since the accuracy is better than the normal 'dead reckoning' method.
    Also, I can't see why S and P mode couldn't be offered with AIS lenses on a modern DSLR if the body had the mechanism that reads the cutout on the lens to tell an AIS lens from an AI one or it might try S or P mode on an AI lens. That wouldn't work since the camera body can't use the slow 'light feedback' closed loop stop-down method.
    Jay, to answer your last question. My guess is that the F4 and F5 are probably not capable of telling an AIS lens from an AI one and since they can't stop the lens down using the slow closed loop method of stop down (used by the FA and FG for example) they don't offer the option of P and S mode because they might be used on an AI lens whch would in turn result in incorrect exposure.
     
  33. "In fact the ring on the AI/AIS lenses doesn't feed the aperture to the camera; it feeds in the amount below maximum aperture the lens is (or rather will be) stopped down."
    This is the "perfect" way of explaining it... but I don't know if it will be understandable by all... In fact, the coupling ring of AI/AI-s lenses (which is still present on the models that offer Non-CPU lens coupling), does nothing more than replacing the old prong coupling of the 60's cameras to the build in metering and it does so mechanically. Nikon, is the only imaging company at present, which when the body sets shutter speed automatically this is done electronically, but when aperture is set automatically, only the order is electronic, the final action is mechanical and is performed by the lever behind the lens which is there originally to provide the DOF preview!
    Richard is also right when he says that "it can be offered" ("I can't see why S and P mode couldn't be offered.."), IMO it is purely the additional cost and complexity that is involved to make the coupling (mount) ring communicate as an extra command with the camera's control system, (not only with the metering as it is today) and the fact that a second (cheaper) control system would be necessary for the low cost cameras that not offer AI coupling. Also, (I like this) the fact that the company thinks of P & S modes as non important for photographers.... at least for the ones that would use an AI/AI'd/AI-s lens. After all, FA was never able to compete with FE-2 sales, despite its "fancy" metering, the modes and the "stupid" F3-like viewfinder info... didn't FE/FE-2/FM-3 offer the best viewfinder info of all times? ...and all the features that a photographer will ever need?
     
  34. Mind you that P will also work correctly.... but in reality, it's exactly the same as using A mode because aperture can't be adjusted from the camera... Still, exposure will be correct.​
    Thanks Theodoros, I wasn't aware of that. So in P, it will effectively act as in A....makes sense.
     
  35. I've experienced that a Nikkor manual focus AI/ AIS lens will only work and meter properly on multi mode DSLR or 35mm SLR bodies in A or M modes only! I do have a 45mm f2.8P that works in all modes with exception of auto focus on all Nikons!
     
  36. "I do have a 45mm f2.8P that works in all modes..."​
    And therein lies the solution. Add a CPU chip (such as the "Dandelion") to your manual focus Nikkors if you really want to use them in P or S modes on bodies other than the FA, FG, etc. :)
    Technically I can think of no reason why Nikon could not have allowed for P and S exposure mode compatibility with AiS lenses on all current and past Nikon DSLR bodies without the need for any additional mechanical hardware. All that should be required is the necessary programming to allow entry of non-CPU lens data (focal length and maximum aperture) and the supporting exposure control firmware. Once the camera has that info it is in essence working with an Ai-P CPU lens like the 45mm f/2.8P. Lower level bodies without an Ai tab could control aperture via the command dial in all exposure modes, just as they do for AF-D lenses. Higher level bodies with an Ai tab could control the aperture via command dial in S and P modes, and by aperture ring or command dial in A and M mode, also as they can do with a AF-D lens.
    Nikon has chosen to completely/partially cripple DSLR compatibility with non-CPU manual focus lenses by not including the necessary firmware for P and S modes. If one believes Nikon is a benevolent dictator with their customers best interests at heart, then we might guess that perhaps this option was chosen for maximum backward compatibility with pre-AiS lenses, and to prevent problems that would occur if the earlier Ai or non-Ai lenses (with their non-linear aperture motion and resulting exposure errors) were inadvertently used with body controlled aperture stopdown. After all, the vast majority of Nikon users are completely clueless as to the difference between Ai and AiS lenses. Heck, I've come across a few who assumed that you could autofocus a manual focus lens by mounting it on an autofocus body.
    On the other hand if one is cynical, then we might guess that perhaps this decision was made to increase the probability of customers upgrading to new autofocus CPU lenses if P and S mode compatibility was important. After all, Nikon is primarily in the business of selling lenses, not designing legacy support for older dead product lines. >:) ;-)
    You decide. :)
    Of course the real kick in the teeth with respect to the F4 was that it does have all the necessary mechanical devices for P and S mode compatibility with AiS lenses, just like the FA. It has an AiS detection pin on the mount to activate PHi mode, and a lens speed post lever inside the mirror box (4 to 6 o'clock position) to mechanically communicate the actual maximum lens aperture to the camera (hence the reason why the F4 is the only autofocus 35mm camera other than the F6 that can matrix meter with Ai or AiS lenses). Nikon for whatever reason simply chose not to include the necessary programming to make full use of those two mechanical parts.
    Perhaps there was no room left on the ROM chips for closed loop metering and all that other good stuff? ;-) :)
    00biww-540672684.jpg
     
  37. But if the F4 works in S and P mode with AI-S lens it can not display the aperture in viewfinder. The FA can't either but may be that's unacceptable for a professional camera.
     
  38. But if the F4 works in S and P mode with AI-S lens it can not display the aperture in viewfinder.​
    Yes it could. As Michael points out above, the F4 can read the lens speed post on an AI-S lens and since it will then know the lens' maximum aperture and also how far it will be driving the stop down lever it could display the final aperture on the LCD. The lens aperture ring will be set to minimum aperture and so the optical display will display the minimum aperture but that is no different from the display with an autofocus lens.
     
  39. Michael,
    You wrote that the F4 has an AiS detection pin on the mount to activate PHi mode. When I wrote earlier why I thought the F4 was unable to do S and P modes with an AI-S lens I assumed that it lacked this pin but after reading the instruction book I saw that it had. Please can you explain why/how it makes use of this pin to enable/disable high speed program - I just don't get it.
    While the backwards compatability with the new DSLRs is a little lacking I'm still pretty impressed. Having recently bought a D7000 at last I have a camera that is reasonably portable and has the required fittings (aperture feeler, ability to set lens info etc.). I was then able to pop on my 1980's 50 mm f/1.8 AI-S and low and behold it works better than it did on my FE2 and F90x since I have both aperture clearly visible in the viewfinder and an excellent electronic rangefinder which with my eyesight I find better than the old split image or microprism!
     
  40. AI-S zoom lenses with non-constant aperture
    I haven't ever looked closely at one of these but I bet the lens speed post is fixed. If so it means that the camera will not be told the true maximum aperture of the lens at all zoom settings; it probably indicates the max. aperture when zoomed out. If so then if P and S modes were offered the result would be underexposure on the DSLRs and most of the film cameras too. Is that the reason why it isn't available on the F4 I wonder? There probably aren't more than about 5 Nikon lens designs like that.
     
  41. That'll teach me to have an internet-free weekend...

    Fortunately Michael did a sterling job for me.

    Richard: Bear in mind that variable-aperture zooms that aren't G already have a problem with their aperture rings - the ring doesn't move, and there are just two marks on the lens indicating the aperture at the extremes of the zoom range. I've no experience with these. However, the aperture lever does just say how far to stop down from the current "wide open" position - if you hold down the DoF preview on a D700 (say) and zoom a variable aperture lens (the D700 can't move the aperture lever without cycling it back to wide open, unlike the D3 or D800), the brightness changes visibly. Release and re-press the DoF preview button and it moves to a different place; I'm sure the varying aperture is communicated only electronically, though how much difference the "wrong" aperture would really make to an exposure is debatable, given that it's relative to a metered wide-open value: I'm not sure how valuable it is to report the exact aperture to the camera. AI (and maybe even AF non-D?) lenses have no way to tell the camera that the aperture is varying with focal distance either, yet the wonders of TTL metering mean that everything just works.

    I now want an F4 to play with. Although I did anyway...
     
  42. Theodoros is incorrect in saying that only Nikon sets the aperture mechanically. Pentax does also. The lever has always been there in both makes primarily to close the auto-diaphragm, with DoF preview secondary.
     
  43. Dear All,
    Sorry for digging out this old thread. I have an F4 and have trouble operating it in P and S modes. For some reason, the camera seems no matter what to always stop down the lens to the minimum aperture possible, say if I read f/2 or f/5.4 in the viewfinder the lens gets stopped down to f/22 and I get a blinking red locking the camera.
    This happens with the AF D lenses, and in the P/S modes only. Also, when I press the DOF/mirror lock up button I see the lens stops down to f/22 (min aperture value locked). Am I doing something wrong, or it is a fault of the camera?
    Thank you
     

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